The present invention relates to automotive latching devices and, in particular, to a solenoid actuated self-compensating latch mechanism particularly adapted for use with a fuel filler door latch system to prevent unauthorized access to the fuel tank.
In an effort to inhibit unauthorized access to a vehicle's fuel tank, automobile manufacturers are evaluating various fuel filler door latch systems. Conventionally, fuel filler door latch systems have included the use of a striker fixed to the filler door and a latch member ("hook") mounted to the vehicle body. The latch member engages the striker to lock the fuel filler door in a "latched" position. To release the fuel filler door, the latch member is moved to an "unlatched" position to disengage the striker. The fuel filler door is spring loaded to open partially when the latch member moves to the "unlatched" position for allowing the operator to pivot the door to a full open position.
One method of locking the fuel filler door includes the use of a key lock mechanism. However, as a convenience option, vehicle manufacturers are installing remotely actuated fuel filler door latch release systems. Such remotely actuated systems permit an occupant within the passenger compartment of the vehicle to release the fuel filler door prior to exiting the vehicle. Typically, remotely actuated latching systems include the use of linear actuation cables or linkages for manually releasing the filler door. In general, a vehicle occupant pulls a release handle within the passenger compartment to move the latch member out of engagement with the striker. As an alternative, many vehicles are now being equipped with electrically actuated release systems. Electrically actuated systems include a solenoid device mounted remote from the fuel filler area and a linkage coupled between a movable solenoid armature and the latch member. Energization of the solenoid moves the armature and, consequently, the latch member to disengage the striker.
Because the fuel filler door is a cosmetic "fit and finish" component of an automobile, it must be precisely aligned during assembly. It is common for conventional fuel filler latching mechanisms to require adjustment of the alignment between the latch member and the striker following vehicle assembly to assure the release system will function properly.
A disadvantage associated with "prior art" solenoid operated fuel filler latching mechanisms is the excessive armature travel required to assure adequate system reliability. Conventional solenoid actuated release systems must generate a large armature travel to account for the dimensional variations associated with the components making up a fuel filler door assembly and the latch mechanism. As is known in solenoid design, it is an inherent characteristic that the magnetic attractive force produced by a solenoid device decreases as its armature travel increases. Therefore, to assure release of the striker it has been necessary to provide an extremely large and expensive solenoid to generate a sufficient force output with a sufficiently large travel. Consequently, solenoid actuated fuel filler door latch systems have, until recently, been extremely expensive due to large solenoid requirements to account for dimensional and alignment variations.
Accordingly, it is a primary object of the present invention to overcome the disadvantages of the prior art and provide an improved latching apparatus having means for compensating for dimensional variations to permit application of smaller, lighter and less expensive solenoids. In particular, the present invention includes a solenoid actuated self-compensating latch mechanism for minimizing the effects of dimensional variations which previously had to be accounted for by the solenoid. Because dimensional variations and tolerance "stack-ups" associated with production assembly operations can be compensated for without impacting solenoid travel requirements, the travel requirement of the solenoid is substantially reduced.
In general, this is accomplished by providing a self-compensating latch mechanism which is coupled to the movable armature of a solenoid. The solenoid and latch mechanism can be assembled to define a compact, unitary, solenoid/latch assembly. Likewise, the solenoid/latch assembly can be mounted to a fuel filler housing to define a fuel filler housing assembly which can be readily installed as a subassembly into the vehicle. The self-compensating latch mechanism permits the magnetic attractive force requirements for a solenoid to be predicated on a substantially reduced amount of armature travel for releasing the latch from the striker. Therefore, the overall size and electrical power requirements of the solenoid can be reduced.
The latch mechanism of the present invention includes a support frame adapted to be mounted to a motor vehicle structure. The support frame supports an elongated carrier member which is pivotally mounted thereto to provide the self-compensating latching function. A latch arm is pivotally carried on the carrier member, independent of the support frame, and is coupled to the movable armature of the solenoid. When a lid or door member is closed, the striker initially contacts the carrier member to pivotally align the latch arm relative to the striker prior to engagement therewith. The pivotal movement of the carrier upon contact with the striker compensates for the dimensional variability inherent in assembly of door latch assemblies. Thereafter, the striker contacts the latch arm to pivot the latch arm until the striker is latched thereto.
To release the striker, the solenoid device is actuated to cause the latch arm to disengage the striker. Consequently, the present invention provides increased reliability, is relatively simple and inexpensive to manufacture, and is convenient for subassembly into a vehicle.
Additional objects and advantages of the present invention will become apparent from a reading of the following detailed description of the preferred embodiments which makes reference to the accompanying drawings.